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000
FXUS65 KBYZ 140253
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
853 PM MDT MON MAY 13 2013

.UPDATE...
STRONGEST FORCING WAS NORTH OF THE FORECAST AREA...ALONG WITH THE
BETTER MOISTURE. THUS...NOT MUCH GOT GOING THIS EVENING. THE UPPER
TROUGH RESPONSIBLE FOR THE CONVECTION TO THE NORTH WILL DRIVE
ACROSS NORTHERN AND CENTRAL MONTANA TONIGHT. THE TAIL END OF
CONVECTION WAS JUST WEST OF BUTTE...MOVING NORTHEAST. CURRENT
TRACK WOULD GRAZE THE NORTHWEST PART OF THE AREA LATE THIS
EVENING. TRIMMED BACK POPS QUITE A BIT ACROSS MOST OF THE AREA
THIS EVENING...BUT LINGERED LOW POPS OVER THE FAR NORTH. COLD
FRONT MOVING ACROSS NORTHERN AND WESTERN MONTANA AND SHOULD MOVE
THROUGH BILLINGS AFTER MIDNIGHT. RAIN COOLED AIR BEHIND THE FRONT
WITH READINGS IN THE 50S. THIS AIRMASS SHOULD GET DOWN INTO THE
AREA LATE TONIGHT. LOW DEWPOINTS AND DECREASING WINDS SHOULD ALSO
HELP LOWS GET INTO THE 50S BY MORNING. DROPPED LOWS A COUPLE
DEGREES AT BILLINGS WITH THIS IN MIND. TWH

&&

.SHORT TERM...VALID FOR TUE AND WED...

THE FORECAST CONTINUES ON TRACK THIS AFTERNOON WITH TEMPERATURES
ALREADY IN THE UPPER 80S TO LOW 90S ACROSS THE AREA AND RELATIVE
HUMIDITIES AROUND 15 PERCENT. THE MAIN CONVECTIVE THREAT CONTINUES
TO BE FOR AREAS NORTHWEST OF BILLINGS ALONG A SURFACE BOUNDARY AND
AHEAD OF THE RIDGE-CRASHING PACIFIC TROUGH. VISIBLE SATELLITE
IMAGERY SHOWS A CUMULUS FIELD DEVELOPING OVER THE LAST FEW HOURS
OVER NORTHEASTERN IDAHO AND SOUTHWESTERN MONTANA WHICH CORRELATES
TO INCREASING SHOWER COVERAGE ON RADAR. EXPECT TO SEE SOME
ISOLATED TO SCATTERED THUNDERSTORMS OVER WESTERN ZONES THROUGH
THIS EVENING. GIVEN THE VERY DRY SURFACE CONDITIONS...WITH DEW
POINTS IN THE 30S...SOUNDINGS SHOW A DEEP INVERTED-V SOUNDING
WHICH MAKES THE PRIMARY CONCERN WITH THESE STORMS GUSTY WINDS AND
DRY LIGHTNING. THE CONVECTIVE THREAT WILL DISSIPATE OVERNIGHT AS
THE COLD FRONT IS EXPECTED TO SURGE ACROSS THE FORECAST AREA FROM
NORTHWEST TO SOUTHEAST.

STRONG WINDS ARE STILL EXPECTED BEHIND THE COLD FRONT FOR THE DAY
TUESDAY AND WILL DIMINISH FROM WEST TO EAST THROUGH THE AFTERNOON.
SYNOPTIC SUBSIDENCE AND MIXING BEHIND THE COLD FRONT AND SHORTWAVE
TROUGH WILL HELP TO BRING HIGHER MOMENTUM AIR TO THE SURFACE. THE
STRONGEST WINDS ALOFT...50+ KNOTS BETWEEN 850 AND 700 MB ARE WILL
MOVE EAST INTO THE DAKOTAS BY LATE MORNING...SO THE HIGH WIND
THREAT FOR THE AREA SHOULD BE LOW. HOWEVER...WINDS WILL STILL BE
STRONG ACROSS THE PLAINS WITH GUSTS OF 40 TO 50 MPH POSSIBLE.

TEMPERATURES WILL RECOVER SLIGHTLY ON WEDNESDAY AS SOME SHORTWAVE
RIDGING DEVELOPS ALOFT IN AN OTHERWISE ZONAL FLOW. HOWEVER...THIS
WILL STILL MEAN TEMPERATURES MAINLY IN THE 70S. WEDNESDAY WILL
ALSO BE A DRY DAY BEFORE A CHANGE TO A SLIGHTLY WETTER PATTERN.
CHURCH

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

TRANSITION FROM A STRONG RIDGE TO A PERSISTENT TROF ALOFT WILL
TAKE PLACE THURSDAY INTO FRIDAY...WITH TROF REMAINING IN PLACE
THROUGH MUCH OF NEXT WEEK. THIS WILL INCREASE THE CHANCES FOR
SIGNIFICANT PRECIPITATION ACROSS THE AREA AND PUSH TEMPERATURES
BACK TOWARD NORMAL FOR MID MAY. MODELS BRING A SURGE OF GULF
MOISTURE INTO FAR EASTERN MONTANA THURSDAY FOR THE BEST CHANCE OF
SHOWERS AND THUNDERSTORMS. INCREASED PRECIPITATION CHANCES ABOUT
10 PERCENT THROUGH THE EXTENDED TO LINE UP WITH SURROUNDING
OFFICES AND LATEST MODEL TRENDS...BUT GIVEN THE RECENT MODEL TREND
OF WAY OVER FORECASTING CONVECTION AM RELUCTANT TO GO ANY HIGHER
THAN CHANCE POPS UNTIL WE SEE STRONGER DYNAMICS AND BETTER
MOISTURE ADVECTION. CHAMBERS

&&

.AVIATION...

A COLD FRONT WILL BEGIN MOVING FROM NORTHWEST TO SOUTHEAST ACROSS
THE AREA AFTER 5Z TONIGHT WITH WEST TO NORTHWEST WINDS
OCCASIONALLY GUSTING GREATER THAN 25 KTS THROUGH TUESDAY. ALONG
AND AHEAD OF THE COLD FRONT...HIGH- BASED SHOWERS AND ISOLATED
THUNDERSTORMS ARE POSSIBLE...WITH GUSTY WINDS...BUT LITTLE RAIN.
OUTSIDE OF SOME MOUNTAIN OBSCURATIONS...LOOK FOR MAINLY VFR
CONDITIONS THROUGH TUESDAY EVENING. STC

&&

.PRELIMINARY POINT TEMP/POPS...

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 058/074 045/076 052/075 052/071 050/070 048/062 044/064
    11/N    11/B    12/T    34/T    43/T    33/T    33/T
LVM 050/074 039/076 046/073 045/067 042/067 041/061 039/062
    11/N    12/T    23/T    34/T    44/T    43/T    33/T
HDN 058/076 044/078 050/078 051/076 051/072 048/065 040/065
    10/N    01/B    12/T    34/T    43/T    33/T    33/T
MLS 058/074 045/077 051/077 051/075 052/071 046/065 041/066
    20/N    01/B    12/T    34/T    43/T    33/T    33/T
4BQ 057/075 044/077 050/076 051/075 054/070 047/063 039/063
    10/N    01/B    12/T    34/T    43/T    33/T    33/T
BHK 055/071 043/074 047/074 045/071 050/071 042/062 039/063
    20/N    01/B    13/T    34/T    55/T    44/T    33/T
SHR 054/074 040/075 045/075 046/072 048/068 043/059 035/060
    10/N    01/B    12/T    33/T    44/T    33/T    33/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
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